Conventional buckles for swimming fins include, for example, two parts: a first part connected to a side of the shoe and a second part joined to a strap, the first and second parts being in snap engagement with one another. While useful, buckles of this type have been found disadvantageous in that they must necessarily be loosened to enable the fin to be put on the user's foot, and require adjustment of strap tension each time the fin is put on.
Accordingly, a buckle for swimming fins was developed that could be opened without separating the buckle into two separate parts. Specifically, both a portion of the buckle that is integral with a side of the shoe and a portion attached to an end of the strap are articulated to one another through a connection lever. This lever allows the portion connected to the strap to be moved from a position of engagement with the portion of the buckle connected to the side of the shoe (where the strap tightens the foot of the user at the rear) to a position of disengagement in which the portion to be attached to the strap is moved rearwardly relative to the fixed portion. In this manner, tension of the strap is eliminated, allowing the user to put the fin on his/her foot or remove it. Although useful, the portions that comprise the buckle are inseparable. As a result, it is not possible to separate the strap from the fin. One disadvantage of this buckle arrangement is that, in order to take the fin off, albeit with the strap loosened, the user must always remove it from his/her foot. More specifically, it is necessary that the user pass the loosened strap behind the heel with the aid of his/her hand, if necessary, which can delay operation in emergency situations.
In the buckle, the portion joined with the strap is attached by a snap connection to the portion of the buckle that is integral with the shoe, both during the opening phase and the closure phase, the snap connection being between the intermediate articulation lever and a pair of side flanges rising from the portion integral with the shoe. To open the buckle, however, the user must push the free end of the lever outwardly.
Another disadvantage of this system is that it has been found generally unsafe, in that (i) impact to the device can accidentally cause the buckle to open, and (ii) in the event that the free end of the lever becomes entangled in some external projection.
A further drawback is that, once the fin is worn on the user's foot and the buckle is closed, the tension of the strap can be increased but not decreased. More specifically, when the fin is on, the length of the strap provides relatively tight adherence to the user's foot and has a free end that may be grasped by the user and pulled to increase the tension of the strap. In order to decrease strap tension, however, the user must necessarily insert a few of his/her fingers between their foot and the strap, which is taut, making the task of inserting the user's fingers very difficult. Hence, once the fin is worn on the user's foot, if it appears to be too tight, the strap must be opened and the adjustment operation repeated.